$hf: 12vw;
* {
  box-sizing: border-box;
}
a {
  text-decoration: none;
}
input {
  border: none;
  outline: none;
}
//类
.btn_default {
  color: #fff;
  border: none;
  border-radius: 1vw;
}
.ellipsis{
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.title {
  font-weight: 600;
}
.header, .footer{
  position: relative;
  height: $hf;
  background: #428eee;
}
.f {
  display: flex;
}
.f-c {
  @extend .f;
  justify-content: center;
}
.f_c {
  @extend .f;
  align-items: center;
}
.f-sb {
  @extend .f;
  justify-content: space-between;
}
.f-c_c {
  @extend .f-c;
  align-items: center;
}
.f-sb_c {
  @extend .f-sb;
  align-items: center;
}
.t-center {
  top: 50%;
  transform: translateY(-50%);
}
.l-center {
  left: 50%;
  transform: translateX(-50%);
}
.top-center {
  @extend .t-center;
  position: absolute;
}
.left-center {
  @extend .l-center;
  position: absolute;
  
}
.lt-center {
  @extend .left-center;
  @extend .t-center;
}
.cover {
  position: fixed;
  background-color: rgba(0,0,0,.6);
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
}
